Integrated circuits may perform analogue and digital functions according to required specifications. Such integrated circuits are supplied by a supply voltage generated by a power supply source. This power supply source may be external to the integrated circuit. However, this external power supply source may not be stable enough for supplying the integrated circuits because the external power supply source may supply many circuits with different voltage and current requirements.
For example, in automotive applications, the power supply source is a battery of a vehicle which supplies all integrated circuits in the vehicle.
To this purpose, reference circuits and linear regulators which generate stable reference signals, are typically used to supply internal integrated circuit functions.
Said reference circuits are supplied by the power supply source, thereby any transient perturbations, especially relatively large and fast transient perturbations of the supply voltage, may reflect in a corresponding disturbance of the reference signal over time. Low power reference circuits are typically designed to withstand slow changes of the supply voltage, but not to withstand said relatively fast transient perturbations. If said fast and large transient perturbations are greater than 10 Volt per microsecond or faster, with more than 10 volt peak to peak, the reference signal may be disadvantageously affected, causing malfunctions of the integrated circuit or undesired resetting thereof.
Such fast transient perturbations, known in the art as electrical fast transients (EFT), may be caused by electromagnetic interferences (EMIs), electrostatic discharge (ESD) signals, International Organization for Standardization (ISO) pulses, or the like.
In order to prevent said malfunctions or resets, external capacitors or transient voltage suppressors (TVSs) are used in parallel to the external power supply source to suppress these electrical fast transients. However, external capacitors or TVSs are large and expensive discrete components. Thereby there is a need for a solution that while efficiently suppresses EFTs in integrated circuits is cheaper and smaller than external capacitors or TVSs.